A plan for the total synthesis of the biologically active quassinoids quasimarin and bruceantin is described in this proposal. The preparation of several deoxy analogs is also discussed. The natural products and analogs will be submitted for testing to the National Cancer Institute. Additionally, several intermediates that might serve as pro-drugs will also be submitted for testing. The synthetic plan includes several highly stereoselective reactions and should be amenable to considerable variation. In addition to providing a synthetic source for the natural products and analogs, this project will provide insight into the structure-acitivity relationships of this important class of molecules.